This European Standard specifies the requirements for clay/ceramic flue blocks with solid walls or walls with vertical perforations including bonding and non-bonding blocks and their fittings. Non-bonding flue blocks which have insulation in the vertical perforations or attached to the outer walls are also covered by this standard. This standard specifies the performance requirements for factory-made flue blocks. When they are installed, they will form a part of a multi-wall chimney or a complete chimney which will serve to convey products of combustion from fireplaces or heating appliances to the atmosphere. This standard includes components used for domestic and industrial chimneys which are not structurally independent (free-standing). Testing, marking and inspection requirements are covered by this standard. NOTE 1 Flue blocks covered by this standard are manufactured in three forms : a) single flue ; b) multi-flue ; c) flue/ventilation combination. NOTE 2 Flue blocks may have flues which are either circular, square or rectangular. The joints may have a locating feature such as a rebate.